content: /*
   * Licensed to the Apache Software Foundation (ASF) under one
   * or more contributor license agreements.  See the NOTICE file
   * distributed with this work for additional information
   * regarding copyright ownership.  The ASF licenses this file
   * to you under the Apache License, Version 2.0 (the
   * "License"); you may not use this file except in compliance
   * with the License.  You may obtain a copy of the License at
   *
   *     http://www.apache.org/licenses/LICENSE-2.0
   *
   * Unless required by applicable law or agreed to in writing, software
   * distributed under the License is distributed on an "AS IS" BASIS,
   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
   * See the License for the specific language governing permissions and
   * limitations under the License.
   */
  
  package varaha.text;
  
  import java.io.IOException;
  import java.io.StringReader;
  import java.util.Iterator;
  import java.util.Set;
  import java.util.HashSet;
  
  import org.apache.pig.EvalFunc;
  import org.apache.pig.data.Tuple;
  import org.apache.pig.data.TupleFactory;
  import org.apache.pig.data.DataBag;
  import org.apache.pig.data.BagFactory;
  
  import java.io.FileReader;
  import java.io.IOException;
  import java.util.List;
  
  import edu.stanford.nlp.ling.CoreLabel;
  import edu.stanford.nlp.ling.HasWord;
  import edu.stanford.nlp.process.CoreLabelTokenFactory;
  import edu.stanford.nlp.process.DocumentPreprocessor;
  import edu.stanford.nlp.process.PTBTokenizer;
  
  /**
   * TokenizeText uses the Lucene libraries StandardAnalyzer class to tokenize a
   * raw text input. A list of the stopwords used is available {@link StopWords}.
   * Output is a pig bag containing tokens.
   *  
   * <dt><b>Example:</b></dt>
   * <dd><code>
   * register varaha.jar;<br/>
   * documents    = LOAD 'documents' AS (doc_id:chararray, text:chararray);<br/>
   * tokenized    = FOREACH documents GENERATE doc_id AS doc_id, FLATTEN(StanfordTokenize(text)) AS (token:chararray);
   * </code></dd>
   * </dl>
   * 
   * @see
   * @author Jacob Perkins
   *
   */
  public class StanfordTokenize extends EvalFunc<DataBag> {
  
      private static TupleFactory tupleFactory = TupleFactory.getInstance();
      private static BagFactory bagFactory = BagFactory.getInstance();
  
      public DataBag exec(Tuple input) throws IOException {
          if (input == null || input.size() < 1 || input.isNull(0))
              return null;
  
          // Output bag
          DataBag bagOfTokens = bagFactory.newDefaultBag();
                  
          StringReader textInput = new StringReader(input.get(0).toString());
          PTBTokenizer ptbt = new PTBTokenizer(textInput, new CoreLabelTokenFactory(), "");
  
          for (CoreLabel label; ptbt.hasNext(); ) {
            label = (CoreLabel)ptbt.next();
            Tuple termText = tupleFactory.newTuple(label.toString());
            bagOfTokens.add(termText);
          }
          
          return bagOfTokens;
      }
  }
  